CN trains meet on the double main tracks near Byron, Wisconsin. Going away from us is 331, a heavy train with 132 cars, while climbing the hill slowly toward us is train 510. The 510 performs switching duties along the northern end of the Waukesha Subdivision before making a left turn at Duplainville for the final leg of their trip into Milwaukee over Canadian Pacific. Today's 510 train is particularly late -- ordinarily, the crew would have been tied up in Milwaukee by now!